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1812. Determine Color of a Chessboard Square
Description
You are given coordinates, a string that represents the coordinates of a square of the chessboard. Below is a chessboard for your reference.
Return true if the square is white, and false if the square is black.
The coordinate will always represent a valid chessboard square. The coordinate will always have the letter first, and the number second.
Example 1:
Input: coordinates = "a1" Output: false Explanation: From the chessboard above, the square with coordinates "a1" is black, so return false.
Example 2:
Input: coordinates = "h3" Output: true Explanation: From the chessboard above, the square with coordinates "h3" is white, so return true.
Example 3:
Input: coordinates = "c7" Output: false
Constraints:
coordinates.length == 2'a' <= coordinates[0] <= 'h''1' <= coordinates[1] <= '8'
Solutions
Solution 1: Find the Pattern
By observing the chessboard, we find that two squares $(x_1, y_1)$ and $(x_2, y_2)$ with the same color satisfy that both $x_1 + y_1$ and $x_2 + y_2$ are either odd or even.
Therefore, we can get the corresponding coordinates $(x, y)$ from coordinates. If $x + y$ is odd, then the square is white, return true, otherwise return false.
The time complexity is $O(1)$, and the space complexity is $O(1)$.
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class Solution { public boolean squareIsWhite(String coordinates) { return (coordinates.charAt(0) + coordinates.charAt(1)) % 2 == 1; } } -
class Solution { public: bool squareIsWhite(string coordinates) { return (coordinates[0] + coordinates[1]) % 2; } }; -
class Solution: def squareIsWhite(self, coordinates: str) -> bool: return (ord(coordinates[0]) + ord(coordinates[1])) % 2 == 1 -
func squareIsWhite(coordinates string) bool { return (coordinates[0]+coordinates[1])%2 == 1 } -
function squareIsWhite(coordinates: string): boolean { return ((coordinates.charCodeAt(0) + coordinates.charCodeAt(1)) & 1) === 1; } -
/** * @param {string} coordinates * @return {boolean} */ var squareIsWhite = function (coordinates) { const x = coordinates.charAt(0).charCodeAt(); const y = coordinates.charAt(1).charCodeAt(); return (x + y) % 2 == 1; }; -
impl Solution { pub fn square_is_white(coordinates: String) -> bool { let s = coordinates.as_bytes(); ((s[0] + s[1]) & 1) == 1 } }